Objective: The aim of this study is to explore the therapeutic effect of the PUMA gene mediated by ra- diation-inducible promoters in the treatment of ton- gue squamous cell carcinoma. Methods: Recombi- nant pcDNA3.1 ...Objective: The aim of this study is to explore the therapeutic effect of the PUMA gene mediated by ra- diation-inducible promoters in the treatment of ton- gue squamous cell carcinoma. Methods: Recombi- nant pcDNA3.1 (+)/E-PUMA was constructed, in which the PUMA gene was mediated by a synthetic radiation inducible promoter. The recombined plas-mids were transfected into the Tca8113 cell and xeno- grafts of human tongue squamous carcinoma in na- ked mice respectively. After 24 h, the tumors were tr- eated with 3 Gy of irradiation to upregulate the PU- MA gene expression. PUMA mRNA was detected by RT-PCR. Proliferating cell nuclear antigen (PCNA) and apoptosis were detected by immunohistochemi- cal method and in situ end-labeling (ISEL) respecti- vely. The data were analyzed using the SPSS11.0 soft- ware package for chi-square test. RESULTS: Com-pared with the control group, the comparative survi- val rate of Tca8113 cells in the PUMA/IR group was markedly decreased and the xenografts were signify- cantly suppressed. Up-regulation of PUMA gene ex- pression was observed in the Tca8113 cells and in the xenografts after irradiation. The apoptosis indices of the Tca8113 cells and xenograft with irradiation were markedly higher than those without irradiation. At the same time, the proliferation indices of the Tca- 8113 cells and xenografts with irradiation were mark- edly lower than those without irradiation. Conclu- sions: radiation-induc ible promoters can serve as molecular switches to improve the expression of PU- MA gene in tongue squamous cell carcinoma both in vivo and in vitro. Low-dose induction radiation can significantly improve therapeutic efficiency.展开更多
Genomes consist of DNA and the genetic information is encoded in a linear form of DNA. According to the central dogma of molecular biology, the genetic information is transcribed into mRNA, and mRNA translated into a ...Genomes consist of DNA and the genetic information is encoded in a linear form of DNA. According to the central dogma of molecular biology, the genetic information is transcribed into mRNA, and mRNA translated into a polypeptide. Gene expression should be precisely regulated in order to create progeny. Unlike RNA, DNA has double-stranded structure. Is there any specific biological reason why DNA has evolved to possess double-stranded structure? In this presentation, biological implications of the double-stranded structure of the DNA molecule will be reviewed. In eukaryotes, it has been reported that cells might have the machinery that distinguishes one DNA-strand from the other, and that the strand-recognition mechanism might control development, cancer and evolution. Three prominent models concerning biological implications of replication of double-stranded DNA will be discussed: 1) Klar’s “somatic strand-specific imprinting and selective chromatid segregation model” for differential gene regulation, 2) Cairns’ “immortal strand inheritance model” for cancer prohibition, and 3) the “disparity mutagenesis model” for the acceleration of evolution proposed by the present author.展开更多
In many cases, biological sequence databases contain redundant sequences that make it difficult to achieve reliable statistical analysis. Removing the redundant sequences to find all the real protein families and thei...In many cases, biological sequence databases contain redundant sequences that make it difficult to achieve reliable statistical analysis. Removing the redundant sequences to find all the real protein families and their representatives from a large sequences dataset is quite important in bioinformatics. The problem of removing redundant protein sequences can be modeled as finding the maximum independent set from a graph, which is a NP problem in Mathematics. This paper presents a novel program named FastCluster on the basis of mathematical graph theory. The algorithm makes an improvement to Hobohm and Sander’s algorithm to generate non-redundant protein sequence sets. FastCluster uses BLAST to determine the similarity between two sequences in order to get better sequence similarity. The algorithm’s performance is compared with Hobohm and Sander’s algorithm and it shows that Fast- Cluster can produce a reasonable non-redundant pro- tein set and have a similarity cut-off from 0.0 to 1.0. The proposed algorithm shows its superiority in generating a larger maximal non-redundant (independent) protein set which is closer to the real result (the maximum independent set of a graph) that means all the protein families are clustered. This makes Fast- Cluster a valuable tool for removing redundant protein sequences.展开更多
文摘Objective: The aim of this study is to explore the therapeutic effect of the PUMA gene mediated by ra- diation-inducible promoters in the treatment of ton- gue squamous cell carcinoma. Methods: Recombi- nant pcDNA3.1 (+)/E-PUMA was constructed, in which the PUMA gene was mediated by a synthetic radiation inducible promoter. The recombined plas-mids were transfected into the Tca8113 cell and xeno- grafts of human tongue squamous carcinoma in na- ked mice respectively. After 24 h, the tumors were tr- eated with 3 Gy of irradiation to upregulate the PU- MA gene expression. PUMA mRNA was detected by RT-PCR. Proliferating cell nuclear antigen (PCNA) and apoptosis were detected by immunohistochemi- cal method and in situ end-labeling (ISEL) respecti- vely. The data were analyzed using the SPSS11.0 soft- ware package for chi-square test. RESULTS: Com-pared with the control group, the comparative survi- val rate of Tca8113 cells in the PUMA/IR group was markedly decreased and the xenografts were signify- cantly suppressed. Up-regulation of PUMA gene ex- pression was observed in the Tca8113 cells and in the xenografts after irradiation. The apoptosis indices of the Tca8113 cells and xenograft with irradiation were markedly higher than those without irradiation. At the same time, the proliferation indices of the Tca- 8113 cells and xenografts with irradiation were mark- edly lower than those without irradiation. Conclu- sions: radiation-induc ible promoters can serve as molecular switches to improve the expression of PU- MA gene in tongue squamous cell carcinoma both in vivo and in vitro. Low-dose induction radiation can significantly improve therapeutic efficiency.
文摘Genomes consist of DNA and the genetic information is encoded in a linear form of DNA. According to the central dogma of molecular biology, the genetic information is transcribed into mRNA, and mRNA translated into a polypeptide. Gene expression should be precisely regulated in order to create progeny. Unlike RNA, DNA has double-stranded structure. Is there any specific biological reason why DNA has evolved to possess double-stranded structure? In this presentation, biological implications of the double-stranded structure of the DNA molecule will be reviewed. In eukaryotes, it has been reported that cells might have the machinery that distinguishes one DNA-strand from the other, and that the strand-recognition mechanism might control development, cancer and evolution. Three prominent models concerning biological implications of replication of double-stranded DNA will be discussed: 1) Klar’s “somatic strand-specific imprinting and selective chromatid segregation model” for differential gene regulation, 2) Cairns’ “immortal strand inheritance model” for cancer prohibition, and 3) the “disparity mutagenesis model” for the acceleration of evolution proposed by the present author.
文摘In many cases, biological sequence databases contain redundant sequences that make it difficult to achieve reliable statistical analysis. Removing the redundant sequences to find all the real protein families and their representatives from a large sequences dataset is quite important in bioinformatics. The problem of removing redundant protein sequences can be modeled as finding the maximum independent set from a graph, which is a NP problem in Mathematics. This paper presents a novel program named FastCluster on the basis of mathematical graph theory. The algorithm makes an improvement to Hobohm and Sander’s algorithm to generate non-redundant protein sequence sets. FastCluster uses BLAST to determine the similarity between two sequences in order to get better sequence similarity. The algorithm’s performance is compared with Hobohm and Sander’s algorithm and it shows that Fast- Cluster can produce a reasonable non-redundant pro- tein set and have a similarity cut-off from 0.0 to 1.0. The proposed algorithm shows its superiority in generating a larger maximal non-redundant (independent) protein set which is closer to the real result (the maximum independent set of a graph) that means all the protein families are clustered. This makes Fast- Cluster a valuable tool for removing redundant protein sequences.
